Aim: The influence of metabolic syndrome (MS) on long-term mortality and morbidity in multi-vessel coronary artery disease (MV-CAD) is unclear. We studied the impact of MS on long-term outcomes in non-diabetic patients (NDM) with MV-CAD undergoing coronary revascularization in the Bypass Angioplasty Revascularization Investigation (BARI) trial and registry.
Methods: BARI trial and registry patients were separated into those with diabetes (DM) and those without. NDM fulfilling the NCEP definition of MS were identified. Ten year follow-up data were obtained on mortality, MI and development of diabetes. The data were analyzed using Cox proportional hazard modeling.
Results: In the BARI trial and registry 2962 NDM were identified. Of those, 510 patients had 3 or more components of the BARI-modified NCEP definition for MS, while 445 patients had 2 components of the definition and were classified as the "mixed group". Compared to patients without MS, both MS group (RR=3.2, p<0.0001) and the mixed group (RR=1.9, p=0.02) had a higher incidence of DM over the 10-year follow-up. Type 2 DM was found to be highly associated with 10-year mortality (RR=1.65, p<0.0001). However, there was no statistically significant difference in the rate of death or MI at 5 and 10 years between NDM with or without MS. In multivariate analysis, the presence of MS was not associated with 10-year mortality in the BARI population (RR=0.93, p=0.62).
Conclusion: In this BARI follow-up study, we have affirmed the role of MS in predicting the development of diabetes in NDM at baseline. The 10-year risk of mortality and MI was not greater in NDM with MS who had MV-CAD and underwent revascularization, compared to patients without MS. Further studies to evaluate MS patients with MV-CAD undergoing coronary revascularization are warranted.